Tire pressure monitoring system

Abstract

The present disclosure relates to systems and methods for a tire pressure monitoring system. Embodiments can include receiving an input signal and storing it in a memory; receiving a digital signal from the memory at a digital signal processor, wherein the digital signal processor includes a plurality of selectable filters; filtering the digital signal through the plurality of selectable filters, wherein filtering the digital signal generates a forward filtered digital signal; storing the forward filtered digital signal in the memory; inverting the forward filtered digital signal, wherein inverting the forward filtered digital signal generates an inverted filtered digital signal; and filtering the inverted filtered digital signal through the plurality of selectable filters, wherein filtering the inverted filtered digital signal generates a processed signal.

Description

Technical Field

[0001] The present disclosure applies generally to monitoring systems and, more particularly, to systems and methods for tire pressure monitoring systems. Background Art

[0002] Tire pressure monitoring systems ("TPMS") are electrical systems designed to monitor the air pressure within a vehicle's tires. These systems typically measure tire pressure regularly and in real time to help prevent traffic accidents, poor fuel economy, and improve tire wear. Many countries around the world require the installation of these systems in vehicles because they effectively create a safer driving environment.

[0003] TPMS are typically located inside the tire and have no direct power source. Therefore, any TPMS likely requires battery power. When the battery depletes, the vehicle operator is often required to undergo a time-consuming process of removing the wheel and tire to access the TPMS. In commercial vehicles, this can mean a direct loss of money, either during a complete TPMS replacement or battery replacement. The TPMS market is continually driven by demands to extend the life of the system to reduce downtime and increase the effectiveness of this important safety system.

[0004] TPMS may need to precisely measure the relative position of the wheels. TPMS can monitor the signal from the sensor, but this signal is contaminated by road noise. Traditional analog filters can be used to reduce the effects of this noise, but these analog filters are large, increase phase distortion, and require a lot of energy. Summary of the Invention

[0005] As will be discussed in greater detail below, embodiments of the present disclosure include a tire pressure monitoring system.

[0006] One or more embodiments of the present disclosure include a method associated with a tire pressure monitoring system (“TPMS”). The method may include receiving an input signal at an amplifier. The method may also include generating a first output at the amplifier, wherein the first output has a higher signal level than the input signal. The method may also include receiving the first output at a filter. The method may also include generating a second output at the filter. The method may also include receiving the second output at an analog-to-digital converter. The method may also include generating a third output at the analog-to-digital converter. The method may also include storing the third output in a memory. The method may also include receiving a digital signal from a memory at a digital signal processor, wherein the digital signal processor includes a plurality of selectable filters. The method may also include filtering the digital signal through the plurality of selectable filters, wherein filtering the digital signal generates a forward-filtered digital signal. The method may also include storing the forward-filtered digital signal in a memory. The method may also include inverting the forward-filtered digital signal, wherein inverting the forward-filtered digital signal generates a reverse-filtered digital signal. The method may also include filtering the reverse-filtered digital signal through the plurality of selectable filters, wherein filtering the reverse-filtered digital signal generates a processed signal.

[0007] The method may include one or more of the following features. In some embodiments, the input signal may be periodically transmitted from the source for a transmission time. The method may include disabling the amplifier, the filter, and the analog-to-digital converter after the transmission time of the input signal and after storing the third output in a memory. In some embodiments, the plurality of optional filters may further include an infinite impulse response filter. In some embodiments, the method may further include reprocessing the processed signal. Reprocessing the processed signal may include filtering the processed signal through the plurality of optional filters, wherein filtering the processed signal may generate a second forward-filtered digital signal. Reprocessing the processed signal may also include storing the second forward-filtered digital signal in the memory. Reprocessing the processed signal may also include inverting the second forward-filtered digital signal, wherein inverting the second forward-filtered digital signal may generate a second reverse-filtered digital signal. Reprocessing the processed signal may also include filtering the second reverse-filtered digital signal through the plurality of optional filters, wherein filtering the second reverse-filtered digital signal may generate the reprocessed signal. The method may also include recursively repeating the reprocessing step, wherein recursively repeating the reprocessing step may use the reprocessed signal as the processed signal in the filtering the processed signal step. The method may also include recursively repeating the reprocessing step until the phase of the reprocessed signal is equal to the phase of the digital signal. Some embodiments may include minimizing the filter settling time of the processed signal. Minimizing the filter settling time may include measuring the phase shift between the forward filtered digital signal and the reverse filtered digital signal. Minimizing the filter settling time may also include measuring the minimum Z register value and the maximum Z register value in the forward filtered digital signal. Minimizing the filter settling time may also include correcting the processed signal based on at least the minimum Z register value and the maximum Z register value. Minimizing the filter settling time may also include calculating Z delay register values ​​from the minimum Z register value and the maximum Z register value. Minimizing the filter settling time may also include utilizing Z delay register values ​​in an infinite impulse response filter before filtering the reverse filtered digital signal through a plurality of optional filters. Minimizing the filter settling time may also include applying a phase offset to the start position of filtering of the reverse filtered digital signal.

[0008] In one or more embodiments of the present disclosure, a TPMS system is provided. The system may include an amplifier that may be configured to receive an input signal and generate a first output, wherein the first output may include a signal level that is higher than the signal level of the input signal. A filter may be configured to receive the first output and generate a second output. An analog-to-digital converter may be configured to receive the second output and generate a third output. A memory may be configured to receive the third output, store the third output, and generate a digital signal. A digital signal processor may be configured to receive a digital signal and filter the digital signal through a plurality of optional filters to generate a forward-filtered digital signal. The digital signal processor may also be configured to store the forward-filtered digital signal in the memory. The digital signal processor may also be configured to invert the forward-filtered digital signal to generate a reverse-filtered digital signal. The digital signal processor may also be configured to filter the reverse-filtered digital signal through a plurality of optional filters to generate a processed signal.

[0009] One or more of the following functions may be included. In some embodiments, the input signal may be periodically transmitted from the source within a transmission time. In some embodiments, the amplifier, filter, and analog-to-digital converter are configured to be disabled after the transmission time of the input signal and after the third output is stored in the memory. In some embodiments, the plurality of optional filters may include an infinite impulse response filter. The digital signal processor may be configured to reprocess the processed signal. The digital signal processor may be configured to minimize the filter settling time of the processed signal. The digital signal processor may be configured to measure characteristics of the digital signal and, before filtering the reverse filtered digital signal through the plurality of optional filters, calibrate the infinite impulse response filter with at least Z delay register values, wherein the Z delay register values ​​include a minimum Z register value and a maximum Z register value. The digital signal processor may be configured to apply a phase offset to the starting position of the reverse filtered digital signal.

[0010] In one or more embodiments of the present disclosure, a method associated with a tire pressure monitoring system ("TPMS") is included. The method may include receiving an input signal. The method may also include storing the input signal in a memory. The method may also include receiving a digital signal from the memory at a digital signal processor. In some embodiments, the digital signal processor may include a plurality of selectable filters. The method may also include filtering the digital signal through the plurality of selectable filters. In some embodiments, filtering the digital signal may generate a processed signal. The method may also include minimizing a filter settling time of the processed signal.

[0011] The present invention may include one or more of the following functions. In some embodiments, minimizing the filter settling time of the processed signal may include measuring a phase shift between the forward filtered digital signal and the reverse filtered digital signal. Minimizing the filter settling time of the processed signal may also include measuring a minimum Z register value and a maximum Z register value in the forward filtered digital signal. Minimizing the filter settling time of the processed signal may also include correcting the processed signal based on at least the minimum Z register value, the maximum Z register value, and the phase shift.

[0012] Details of one or more example embodiments are set forth in the accompanying drawings and the following description. Other possible example features and / or possible example advantages will become apparent from the description, drawings, and claims. Some embodiments may not have those possible example features and / or possible example advantages, and some embodiments may not necessarily require those possible example features and / or possible example advantages.

[0013] This Summary is intended to introduce some concepts that are further described below in the Detailed Description. This Summary is not intended to identify essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are included to provide a further understanding of the embodiments of the present disclosure and are incorporated in and constitute a part of this specification. They illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the embodiments of the present disclosure.

[0015] Figure 1 A block diagram illustrating an embodiment of the present disclosure is shown;

[0016] Figure 2 shows a flow chart consistent with an embodiment of a tire pressure monitoring system;

[0017] Figure 3 shows a flow chart consistent with an embodiment of a tire pressure monitoring system;

[0018] Figure 4 A waveform diagram illustrating phase distortion from filtering is shown;

[0019] Figure 5 Waveform diagrams illustrating phase distortion from forward and reverse filters are shown;

[0020] Figure 6 shows a flow chart consistent with an embodiment of a tire pressure monitoring system;

[0021] Figure 7 shows a strip chart consistent with an embodiment of a tire pressure monitoring system;

[0022] Figure 8 shows a waveform diagram illustrating the stabilization of the digital filter after filtering;

[0023] Figure 9 shows a flow chart consistent with an embodiment of a tire pressure monitoring system;

[0024] Figure 10 shows a waveform diagram and Z delay register values ​​consistent with an embodiment of a tire pressure monitoring system;

[0025] Figure 11 A waveform diagram showing the filter error at the start of the signal is shown;

[0026] Figure 12 shows a waveform diagram illustrating a signal before filter stabilization correction; and

[0027] Figure 13 A waveform diagram showing the signal after filter stabilization correction is shown.

[0028] The same reference symbols in different drawings may identify the same elements. DETAILED DESCRIPTION

[0029] The following discussion is directed to certain embodiments. It should be understood that the following discussion is merely intended to enable one of ordinary skill in the art to make and use any subject matter now or later defined by the patent "claims" in any patent that issues herein.

[0030] In particular, the claimed combination of features is not limited to the embodiments and illustrations contained herein, but includes modifications of those embodiments, including portions of embodiments and combinations of elements of different embodiments within the scope of the following claims. It should be understood that in the development of any such actual implementation, as in any engineering or design project, many implementation-specific decisions must be made to achieve the developer's specific goals, such as complying with system-related and business-related constraints, which may vary from implementation to implementation. Furthermore, it should be understood that such development work may be complex and time-consuming, but it will nevertheless be a routine task of design, production, and manufacture for a person of ordinary skill having the benefit of this disclosure. Unless expressly designated as "critical" or "essential," nothing in this application is to be considered critical or essential to the claimed invention.

[0031] It should also be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present invention, a first object or step may be referred to as a second object or step, and similarly, a second object or step may be referred to as a first object or step. The first object or step and the second object or step are two objects or steps respectively, but they should not be considered to be the same object or step.

[0032] Now refer to Figure 1 , provides an embodiment consistent with the present disclosure, which shows a tire pressure monitoring system ("TPMS") 100. The TPMS 100 may include an input signal 110, an amplifier 120, a first output signal 112, a filter 130, a second output signal 114, an analog-to-digital converter 140, a third output signal 116, a memory 150, a digital signal 118, and a digital signal processor 160. The TPMS 100 represents one possible arrangement of interconnections of these components, although it should be noted that other arrangements are also within the scope of the present disclosure.

[0033] In some embodiments, input signal 110 may have a 10 Hz signal. This specific frequency is used as an example only, as any low-frequency signal may be used. Therefore, the phrase "low frequency" as used herein may refer to any frequency in the range of 1-50 Hz. In other embodiments, input signal 110 may be monitored at specified time periods and / or continuously.

[0034] In some embodiments, the input signal 110 may include various types of information related to the wheel. The wheel may be a vehicle wheel, but other wheels and / or tires requiring TPMS 100 may be used without departing from the scope of the present disclosure. This information may include, but is not limited to, the relative position of the wheel, the angle of the wheel, and / or the rotation of the wheel. In operation, when driving on an uneven road, the input signal 110 may be contaminated by noise. For example, the input signal 110 may be corrupted by variable frequency content from the road or other surfaces related to the wheel. Since the input signal 110 includes information related to the wheel, embodiments of the present disclosure are configured to avoid introducing additional signal contamination.

[0035] In some embodiments, input signal 110 may be received at amplifier 120. Amplifier 120 may process the level of input signal 110 so that input signal 110 is at an appropriate level to be processed by filter 130 and / or analog-to-digital converter 140. In other embodiments, more than one amplifier 120 may be used without departing from the scope of this disclosure.

[0036] In some embodiments, the amplifier 120 can be configured to generate the first output 112. The amplifier 120 can increase the signal level of the first output 112 compared to the signal level of the input signal 110. In some embodiments, the amplifier 120 can operate continuously or discontinuously.

[0037] In some embodiments, as Figure 1 As shown, the first output 112 can be fed into a filter 130. In some embodiments, the filter 130 can be any suitable filter, some of which can include, but are not limited to, an aliasing filter, an anti-aliasing filter, and / or a low-pass filter. In other embodiments, the filter 130 can be configured to reduce frequency contamination provided by the surface on which the wheel is traveling. The filter 130 can generate a second output 114, which will be discussed in further detail below.

[0038] In some embodiments, the analog-to-digital converter 140 can be configured to receive the second output 114 from the filter 130. The analog-to-digital converter 140 can convert the second output 114 to a digital format and generate a third output 116. The input signal 110 can be an analog signal and can remain an analog signal as it passes through the amplifier 120 and the filter 130 and is conditioned by the amplifier 120 and the filter 130 as the first output 112 and the second output 114, respectively. In some embodiments, the analog-to-digital converter 140 can operate continuously or discontinuously.

[0039] In some embodiments, the memory 150 can be configured to receive the third output 116 from the analog-to-digital converter 140. The memory 150 can permanently store the third output 116, or can store the third output 116 until the filtering operation in the digital signal processor 160 is completed. The memory 150 can be any memory suitable for storing the third output 116 for read and write operations in the digital signal processor 160. Some types of memory can include, but are not limited to, volatile memory, such as dynamic random access memory or static random access memory (collectively referred to as "RAM"), non-volatile memory, such as flash memory, and any other suitable storage device. The memory 150 can be configured to generate the digital signal 118 and / or can also be configured to receive the digital signal 118 from the digital signal processor 160.

[0040] In some embodiments, digital signal 118 may include samples of input signal 110 or the entire input signal 110. In either case, input signal 110 may be digitized and conditioned by amplifier 120, filter 130, and analog-to-digital converter 140. Typically, memory 150 may store third output 116 as data therein.

[0041] In some embodiments, once the input signal 110 is captured, conditioned, and stored in the memory 150, the amplifier 120, the filter 130, and / or the analog-to-digital converter 140 may be turned off and / or disabled. In such embodiments, since the digital signal processor 160 and the memory 150 may still perform their operations without the amplifier 120, the filter 130, and / or the analog-to-digital converter 140 once the input signal 110 is stored in the memory 150, this operation may result in reduced energy consumption. Thus, using the teachings of the present disclosure, embodiments may use approximately 10% of the energy of existing tire pressure monitoring systems.

[0042] In some embodiments, the digital signal processor 160 may be configured to receive the digital signal 118. In some embodiments, the digital signal processor 160 may send the digital signal 118 back to the memory 150 for storage. The digital signal processor 160 may be configured to process the digital signal 118, which may allow information related to the wheel to be extracted. In some embodiments, the digital signal processor 160 may include a filter or multiple filters. The multiple filters may be different and / or selectable. Some examples of filters may include, but are not limited to, infinite impulse response filters, zero phase filters, forward-reverse filters, and / or any combination thereof. The digital signal processor 160 may be configured to process the digital signal 118 from the memory 150 through multiple filters. In some embodiments, the digital signal processor 160 may be configured to remove phase distortion of the digital signal 118 resulting from the multiple filters. In other embodiments, the digital signal processor 160 may be configured to reprocess the digital signal 118 recursively or a set number of times. In other embodiments, the digital signal processor 160 may be configured to minimize the filter settling time resulting from the filtering operation. More details of the processing operations are provided below with reference to other figures. Specifically, Figure 3 、 Figure 6 and Figure 9 Flowcharts illustrating various processing operations are depicted in accordance with embodiments consistent with the present disclosure.

[0043] Now refer to Figure 2, a flowchart 200 consistent with an embodiment of the TPMS 100 is provided. The method may include receiving (212) an input signal (e.g., input signal 110) at an amplifier (e.g., amplifier 120). The method may also include generating (214) a first output (e.g., first output 112) at the amplifier, wherein the first output has a higher signal level than the signal level of the input signal. The method may also include receiving (216) the first output at a filter (e.g., filter 130). The method may also include generating (218) a second output (e.g., second output 114) at the filter. The method may also include receiving (220) the second output at an analog-to-digital converter (e.g., analog-to-digital converter 140). The method may also include generating (222) a third output (e.g., third output 116) at the analog-to-digital converter. The method may also include storing (224) the third output in a memory (e.g., memory 150). The method may also include receiving (228) a digital signal (eg, digital signal 118) from a memory at a digital signal processor (eg, digital signal processor 160), wherein the digital signal processor includes a plurality of selectable filters.

[0044] In some embodiments of the TPMS 100, the input signal may be periodically transmitted from the source for a transmission time. The method may include disabling (226) the amplifier, the filter, and the analog-to-digital converter after the transmission time of the input signal and after the third output is stored in the memory.

[0045] Now refer to Figure 3 , a flowchart 300 is provided consistent with an embodiment of the TPMS 100. The flowchart 300 may include Figure 2 Specifically, flowchart 300 begins by storing (224) the third output in a memory and receiving (228) a digital signal from the memory at a digital signal processor, wherein the digital signal processor includes a plurality of selectable filters. However, flowchart 300 provides additional details for receiving (228) the digital signal from the memory at a digital signal processor, wherein the digital signal processor includes a plurality of selectable filters.

[0046] In some embodiments, as Figure 3As shown, the method may further include filtering the digital signal through a plurality of selectable filters (310), wherein filtering the digital signal generates a forward-filtered digital signal. The method may further include storing (320) the forward-filtered digital signal in a memory. The method may further include inverting the forward-filtered digital signal (330), wherein inverting the forward-filtered digital signal generates a reverse-filtered digital signal. The method may further include filtering the reverse-filtered digital signal through a plurality of selectable filters (340), wherein filtering the reverse-filtered digital signal generates a processed signal.

[0047] In some embodiments, the digital signal can be filtered (310) while minimizing phase distortion of the processed signal. In other embodiments, the digital signal can be filtered (310) without introducing phase distortion in the processed signal. In some embodiments, filtering the digital signal from the memory at the digital signal processor (310) allows for digital implementation without using excessive physical area (specifically, without requiring additional processing equipment) and without using software correction techniques.

[0048] In some embodiments, filtering the digital signal through a plurality of selectable filters (310) may include an infinite impulse response filter (350) within the plurality of selectable filters. In some embodiments, the plurality of selectable filters may cause phase distortion in the digital signal during a first pass through the filters in the forward filtered digital signal. The phase distortion may be a frequency-dependent effect; however, embodiments of the present disclosure may still correct or eliminate the phase distortion. Figure 4 Examples are provided showing phase distortion before and after filtering without using embodiments of the present disclosure.

[0049] In some embodiments, processing the digital signal may further include inverting the forward filtered digital signal (330), wherein inverting the forward filtered digital signal may generate a reverse filtered digital signal. In some embodiments, the inversion (330) may occur using software, hardware, or a combination thereof. Phase distortion may be frequency dependent, and some embodiments may counteract frequency dependent effects by inverting the forward filtered digital signal. By inverting the forward filtered digital signal, a reverse filtered digital signal may be obtained.

[0050] In some embodiments, filtering the reverse filtered digital signal through the plurality of selectable filters (340) can reverse frequency-dependent effects of the plurality of selectable filters. In other embodiments, filtering the reverse filtered digital signal through the plurality of selectable filters (340) can cancel frequency-dependent effects from the plurality of selectable filters, thereby resulting in zero phase distortion. Zero phase distortion means that after filtering the digital signal (310), the phase of the filtered signal is not shifted, or is shifted by zero samples.

[0051] For example, if signal A having a frequency X passes through a plurality of selectable filters, signal A may be shifted by +10 samples compared to the input signal. Then, if signal A is inverted, the inverted signal A will be shifted by -10 samples. Filtering the inverted signal A through the plurality of selectable filters will still result in phase distortion, but the inverted signal A will be shifted by +10 samples, resulting in zero sample distortion (-10+10=0) in the processed signal A. This example is provided to illustrate a specific mechanism for filtering (310) a digital signal.

[0052] Now refer to Figure 4 , a waveform graph 400 is provided that illustrates the phase distortion resulting from filtering. The waveform graph 400 includes an X-axis representing sampling time 410 and a Y-axis representing amplitude 420. The graph 400 illustrates an input wave 430 and a filtered output wave 440. As can be seen, filtering the input wave 430 causes the peak and resulting phase deviation of the filtered output wave 440. In some embodiments, a filter such as an infinite impulse response filter may produce a phase distortion similar to Figure 4 In some embodiments of the TPMS 100, this phase distortion may directly affect the wheel-related information carried on the input wave and, in some cases, may produce undesirable erroneous readings.

[0053] Now refer to Figure 5 , provides a waveform graph 500 showing phase distortion from a forward filter and a reverse filter. Graph 500 includes an x-axis representing sampling time 510 and a y-axis representing amplitude 520. Graph 500 depicts an input wave 530, a forward filtered output wave 540, and a reverse filtered output wave 550. As can be seen, the filtered input wave 530 shifts the peak of the forward filtered output wave 540, as shown in FIG. Figure 4 However, it can also be seen that in some embodiments, inverse filtering the forward filtered output wave 540 can produce a reverse filtered output wave 550 with zero distortion in phase. In other words, the input wave 530 and the reverse filtered output wave 550 can have similar phases.

[0054] Waveform diagram 500 illustrates a second-order filter. In some embodiments, as in waveform diagram 500, the zero-phase distortion on the output wave 550 of the reverse filtering may be accompanied by an amplitude reduction of twice that expected by a single-order filter. A single-order filter may correspond to the first pass through a plurality of optional filters. In other embodiments, a higher-order filter may be required to process the noise input signal. In some embodiments, the higher-order filter comprises any even number of filters. Specifically, without departing from the scope of the present disclosure, second-order, fourth-order, sixth-order, eighth-order and tenth-order filters can be used. A higher-order filter may also be included in the embodiments of the present disclosure. An even number of filter orders can be adopted so that the forward filter can be negated by the reverse filter.

[0055] Now refer to Figure 6 , a flowchart 600 is provided consistent with an embodiment of the TPMS 100. The flowchart 600 may include Figure 2 and / or Figure 3 In some or all of the steps of the present invention, the flowchart 600 begins by filtering the reverse filtered digital signal through a plurality of selectable filters (340), wherein filtering the reverse filtered digital signal generates a processed signal. In particular, the flowchart 600 includes reprocessing the processed signal (610). In addition, the flowchart 600 includes recursively repeating (630) the reprocessing step, wherein the recursively repeating the reprocessing step uses the reprocessed signal as the processed signal in the step of filtering the processed signal. These steps can be used for higher order filtering operations.

[0056] In some embodiments, the method may further include reprocessing the processed signal (610). Reprocessing the processed signal (610) may include filtering the processed signal through a plurality of optional filters (612), wherein filtering the processed signal may generate a second forward filtered digital signal. Reprocessing the processed signal (610) may further include storing (614) the second forward filtered digital signal in a memory. Reprocessing the processed signal (610) may further include inverting the second forward filtered digital signal (616), wherein inverting the second forward filtered digital signal may generate a second reverse filtered digital signal. Reprocessing the processed signal (610) may further include filtering the second reverse filtered digital signal through a plurality of optional filters (618), wherein filtering the second reverse filtered digital signal may generate the reprocessed signal. By repeating the forward and reverse filtering operations, higher order filtering operations become possible.

[0057] In some embodiments, the method may further include recursively repeating (630) the reprocessing step, wherein the recursively repeating the reprocessing step may use the reprocessed signal as the processed signal in the step of filtering the processed signal. In some embodiments, the reprocessing may be a recursive process in which the final filtered signal from the previous operation is forward filtered and reverse filtered again. The method may further include recursively repeating the reprocessing step until the phase of the reprocessed signal equals the phase of the digital signal (632). In some embodiments, the recursive repetition may continue through higher order filtering operations until zero phase distortion occurs.

[0058] Now refer to Figure 7 , provides a strip diagram 700 consistent with an embodiment of a tire pressure monitoring system. The strip diagram 700 illustrates an example embodiment of an eighth-order bandpass having eight filters 710. As shown in FIG. Figure 5 and Figure 6 As stated, other embodiments having different numbers of filter passes are within the scope of this disclosure.

[0059] Now refer to Figure 8 , waveform graph 800 shows that the digital filter has stabilized after filtering. Waveform graph 800 includes an X-axis representing sampling time 810 and a Y-axis representing amplitude 820. Plotted on waveform graph 800 is an input wave 830 and a filtered output wave 840. In some embodiments, after forward and reverse filtering, zero phase distortion may occur, but the signal may be affected by the stabilization of the digital filter. In waveform graph 800, digital filter stabilization can be seen at the beginning and end of the sample. Specifically, the filtered output wave 840 may not align at the beginning and end of the sample and only match at the center of the sample. In some embodiments, the data mismatch seen in waveform graph 800 may occur after infinite impulse response filtering in the forward and reverse directions at a given frequency.

[0060] Now refer to Figure 9 , a flowchart 900 is provided consistent with an embodiment of the TPMS 100. Flowchart 900 continues Figure 3 In the embodiment, but may include Figure 2 、 Figure 3 and / or Figure 6 Specifically, flowchart 600 begins by filtering the reverse filtered digital signal through a plurality of selectable filters (340), wherein filtering the reverse filtered digital signal generates a processed signal. However, flowchart 900 illustrates an embodiment with additional operations. Specifically, flowchart 900 includes minimizing (910) a filter settling time of the processed signal.

[0061] In some embodiments, as Figure 9 As shown, minimizing (910) the filter settling time may include measuring (912) a phase shift between the forward filtered digital signal and the reverse filtered digital signal. Minimizing (910) the filter settling time may also include measuring (914) a minimum Z register value and a maximum Z register value in the forward filtered digital signal. Minimizing (910) the filter settling time may also include correcting (916) the processed signal based on at least the minimum Z register value and the maximum Z register value. Minimizing (910) the filter settling time may also include calculating (918) Z delay register values ​​based on the minimum Z register value and the maximum Z register value. Minimizing (910) the filter settling time may also include utilizing (920) the Z delay register values ​​in an infinite impulse response filter before filtering the reverse filtered digital signal through a plurality of optional filters. Minimizing (910) the filter settling time may also include applying (922) a phase offset to a start position of filtering of the reverse filtered digital signal.

[0062] In some embodiments, the settling time of multiple selectable filters can be overcome by predicting the input waveform and appending this prediction to the samples being filtered. In some embodiments, the prediction will be filtered first and can be long enough to allow the filter to stabilize before the data of interest enters the filter.

[0063] In some embodiments, removing the settling time without additional energy consumption may require knowledge of the filter delay register values ​​and the phase shift of the signal. In some embodiments, measuring (912) the phase shift between the forward filtered digital signal and the reverse filtered digital signal, and measuring (914) the minimum Z register value and the maximum Z register value in the forward filtered digital signal, may be necessary to correct for the filter settling time. In some embodiments, the minimum Z register value and the maximum Z register value are collected as the sample runs through the filter in the forward direction. In some embodiments, the minimum Z register value ("minZ") and the maximum Z register value ("maxZ") can be added together to obtain an average. In some embodiments, Z delay register values ​​(Z1 and Z2) are obtained from the phase shift position near the end of the sample. (Measuring these Z register values ​​will also be combined with Figure 10 The new Z delay register values ​​are calculated using the following equations:

[0064] mean=maxZ+minZ

[0065] newZ1=-Z2+mean

[0066] newZ2=-Z1+mean

[0067] The calculated newZ1 and newZ2 values ​​can be used in the Z delay registers before running the data backward.

[0068] Now refer to Figure 10 , provides a waveform graph 1000 and Z delay register values ​​consistent with an embodiment of the TPMS 100. Waveform graph 1000 includes an X-axis representing sampling time 1010, a Y-axis representing amplitude 1020, and Z delay register values ​​on a second Y-axis. Graph 1000 depicts an input wave 1030, a filtered output wave 1040, Z1 delay values ​​1050, and Z2 delay values ​​1060. In some embodiments, the final value of the filtered output wave 1040 can be used to find the appropriate Z delay register values ​​for signals with equal but opposite gradients. Line 1070 indicates that the Z values ​​are equal but opposite.

[0069] In some embodiments, the Z delay register values ​​used from the final filtered output wave 1040 may not always have an average value of zero. In some embodiments, it may be necessary to find the last maximum and minimum Z register values ​​in the filtered output wave 1040. The sum of the maximum and minimum Z register values ​​may be used as the average of the Z register values ​​to calculate the Z values.

[0070] In some embodiments, correction using Z delay values ​​can replace the filter settling time with a phase shift from the input wave 1030. This problem will be addressed in Figure 11 discussed in the context of .

[0071] Now refer to Figure 11 , waveform graph 1100 illustrates filter error at the start of a signal consistent with TPMS 100. Waveform graph 1100 includes an X-axis representing sampling time 1110 and a Y-axis representing amplitude 1120. Graph 1100 depicts an input wave 1130, a filtered output wave 1140, and an inverse filtered output wave 1150.

[0072] In some embodiments, such as waveform 1100, once the correction using Z register values ​​is applied, the filter stabilization problem may no longer exist. Specifically, in waveform 1100, the correction can be applied only to the end of the sample. As a result, the reverse filtered output wave 1150 and the filtered output wave 1140 may start at the same point, but may no longer be in line with the input wave 1130. This can be corrected by measuring a known point in the waveform when filtering in one direction and measuring how much that point can be moved when filtering in the other direction. Then, by starting processing from different sample positions, the offset between the known points in the different filtering directions can be applied to the end of the sample. In other embodiments, by obtaining the Z delay register value from an earlier point in the sample, the offset between the known points in the different filtering directions can be applied to the end of the sample.

[0073] Now refer to Figure 12 and Figure 13 Waveform graphs 1200 and 1300 illustrate signals before and after filter stabilization correction, respectively, consistent with TPMS 100. Waveform graph 1200 includes an X-axis representing sampling time 1210 and a Y-axis representing amplitude 1220. Graph 1200 depicts an input wave 1230, a filtered output wave 1240, and an inverse filtered output wave 1250. Graph 1300 includes an X-axis representing sampling time 1310 and a Y-axis representing amplitude 1320. Graph 1300 depicts an input wave 1330, a filtered output wave 1340, and an inverse filtered output wave 1350. In some embodiments, such as waveform 1200, without filter stabilization correction, inverse output 1250 may not align with input wave 1230 at the end of a sample. In other embodiments, such as waveform 1300, applying filter stabilization correction to inverse filtered output wave 1350 may align with input wave 1330 at the end of a sample.

[0074] from Figure 12 and Figure 13 As can be seen from the above, embodiments of the present disclosure increase the available data in the sample. In some embodiments, the available data may increase by 10%-20%.

[0075] As used in any embodiment described herein, the term "circuitry" may include, for example, a single or any combination of hard-wired circuits, programmable circuits, state machine circuits, and / or firmware storing instructions executed by programmable circuits. It should be understood that any operation and / or operating component described in any embodiment or embodiment herein may be implemented in software, firmware, hard-wired circuits, and / or any combination thereof.

[0076] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the present disclosure. As used herein, the singular forms "a," "an," and "the" also include the plural forms, unless the context clearly dictates otherwise. It will be further understood that when used in this specification, the terms "comprises" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0077] The equivalents of the corresponding structures, materials, acts, and means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The specification of the present disclosure is presented for purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure of various embodiments with various modifications as are suited to the particular use contemplated.

[0078] Although certain example embodiments have been described above in detail, those skilled in the art will readily appreciate that many modifications may be made in the example embodiments without materially departing from the scope of the present disclosure as described herein. Accordingly, such modifications are intended to be included within the scope of the present disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover structures described herein that perform the function described, including not only structural equivalents, but also equivalent structures. Thus, while a nail and a screw may not be structural equivalents because a nail utilizes a cylindrical surface to secure wooden parts together while a screw utilizes a helical surface, a nail and a screw may be equivalent structures in the context of fastening wooden parts. Applicant expressly disclaims any limitation under 35 U.S.C. § 112(6) to any claim in this application except to the extent that a claim expressly uses the term "means" and the associated function.

[0079] Having described the disclosure of the present application in detail and by reference to examples thereof, it will be apparent that modifications and variations are possible without departing from the scope of the disclosure as defined in the appended claims.

Claims

1. A method associated with a tire pressure monitoring system ("TPMS"), comprising: receiving an input signal at an amplifier; generating a first output at the amplifier, wherein the first output has a higher signal level than the input signal; receiving the first output at a filter; generating a second output at the filter; receiving the second output at an analog-to-digital converter; generating a third output at the analog-to-digital converter; storing the third output in a memory; receiving a digital signal from the memory at a digital signal processor, wherein the digital signal processor includes a plurality of selectable filters; filtering the digital signal through the plurality of selectable filters, wherein filtering the digital signal generates a forward filtered digital signal; storing the forward filtered digital signal in the memory; Inverting the forward filtered digital signal, wherein inverting the forward filtered digital signal generates a reverse filtered digital signal; and The reverse filtered digital signal is filtered by the plurality of selectable filters, wherein filtering the reverse filtered digital signal generates a processed signal.

2. The method according to claim 1, wherein For the transmission time, the input signal is periodically transmitted from the source, and the method further includes: The amplifier, the filter, and the analog-to-digital converter are disabled after a transmission time of the input signal and after storing the third output in the memory.

3. The method according to claim 1, wherein The plurality of selectable filters includes infinite impulse response filters.

4. The method according to claim 1, further comprising: Reprocessing the processed signal, wherein reprocessing the processed signal comprises: filtering the processed signal through a plurality of selectable filters, wherein filtering the processed signal generates a second forward filtered digital signal; storing the second forward filtered digital signal in the memory; inverting the second forward filtered digital signal, wherein inverting the second forward filtered digital signal generates a second reverse filtered digital signal; and The second reverse filtered digital signal is filtered through the plurality of selectable filters, wherein filtering the second reverse filtered digital signal generates a reprocessed signal.

5. The method according to claim 4, further comprising: The reprocessing step is recursively repeated, wherein the recursively repeating reprocessing step uses the reprocessed signal as the processed signal in the step of filtering the processed signal.

6. The method according to claim 5, wherein: Recursively repeating the reprocessing step occurs until the phase of the reprocessed signal is equal to the phase of the digital signal.

7. The method according to claim 3, further comprising: Minimize the filter settling time of the processed signal.

8. The method according to claim 7, wherein: Minimizing the filter settling time of the processed signal includes: measuring a phase shift between the forward filtered digital signal and the reverse filtered digital signal; measuring a minimum Z register value and a maximum Z register value in the forward filtered digital signal; and The processed signal is corrected based on at least the minimum Z-register value and the maximum Z-register value.

9. The method according to claim 8, wherein Minimizing the filter settling time of the processed signal further includes: Calculating Z delay register values ​​according to the minimum Z register value and the maximum Z register value; and The Z delay register values ​​are utilized in the infinite impulse response filter before filtering the inverse filtered digital signal through the plurality of selectable filters.

10. The method according to claim 7, wherein: Minimizing a filter settling time of the processed signal further comprises applying a phase offset to a start position of filtering of the inverse filtered digital signal.

11. A TPMS system comprising: an amplifier configured to receive an input signal and generate a first output, wherein the first output comprises a signal level higher than a signal level of the input signal; a filter configured to receive the first output and generate a second output; an analog-to-digital converter configured to receive the second output and generate a third output; a memory configured to receive the third output, store the third output, and generate a digital signal; and A digital signal processor is configured to receive the digital signal, filter the digital signal through a plurality of selectable filters to generate a forward filtered digital signal, store the forward filtered digital signal in the memory, invert the forward filtered digital signal to generate a reverse filtered digital signal, filter the reverse filtered digital signal through the plurality of selectable filters, and filter the reverse filtered digital signal to generate a processed signal.

12. The TPMS system according to claim 11, wherein: The input signal is periodically transmitted from a source for a transmission time, wherein the amplifier, the filter, and the analog-to-digital converter are configured to be disabled after the transmission time of the input signal and after the third output is stored in the memory.

13. The TPMS system according to claim 11, wherein: The plurality of selectable filters includes infinite impulse response filters.

14. The TPMS system according to claim 11, wherein: The digital signal processor is configured to reprocess the processed signal.

15. The TPMS system according to claim 14, wherein: The digital signal processor is configured to recursively reprocess the processed signal until a phase of the reprocessed signal is equal to a phase of the digital signal.

16. The TPMS system according to claim 13, wherein: The digital signal processor is configured to minimize a filter settling time of the processed signal.

17. The TPMS system according to claim 16, wherein: The digital signal processor is configured to measure characteristics of the inverse filtered digital signal before filtering the inverse filtered digital signal through the plurality of selectable filters and to calibrate the infinite impulse response filter using at least Z delay register values, wherein the Z delay register values ​​include a minimum Z register value and a maximum Z register value.

18. The TPMS system according to claim 17, wherein: The digital signal processor is configured to apply a phase offset to a starting position of the inverse filtered digital signal.

19. A method associated with a tire pressure monitoring system ("TPMS"), comprising: receiving an input signal; storing the input signal in a memory; receiving a digital signal from the memory at a digital signal processor, wherein the digital signal processor includes a plurality of selectable filters; filtering the digital signal through the plurality of selectable filters, wherein filtering the digital signal generates a processed signal; and Minimize the filter settling time of the processed signal.

20. The method according to claim 19, wherein Minimizing the filter settling time of the processed signal includes: Measuring the phase shift between a forward filtered digital signal and a reverse filtered digital signal, measuring a minimum Z register value and a maximum Z register value in the forward filtered digital signal, and The processed signal is corrected based on at least the minimum Z-register value, the maximum Z-register value, and the phase shift.

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